To my knowledge, there was never any
collaboration between Perma and Avon. Perma P267 was printed in 1953; Avon T-121
appeared in 1956. The illustration was painted by George Erickson. The picture,
in itself, is not so odd. Hardcover publishers had a lot of pull when it came to
placing limits on paperback reprints. Keep in mind that Doubleday's reason for
starting Perma Books was to easily roll its hardcover publications into
paperback. (In 1954, Doubleday sold Perma to Pocket Books.) How the rights wound
up with Avon isn't really important.

Of real interest is the yellow printing on
the cover. It's identical. It's obvious to me that Avon didn't just use the same
illustration here. THEY MADE A COPY OF THE COVER OF THE PERMA BOOK! The other
writing on the Perma cover has simply been cropped out.